9mm "adequate" for black bear? They must be pretty small in your area. If an animal is in the process of attacking a person the only way you could be sure of "optimum" shot placement is to get on right on top of it at contact distance. Shooting into a swirling furball of animal and victim is exceedingly difficult, regardless of how accurate your pistol is.

The only way to find the most accurate ammo for your pistol is to shoot different types/brands. What shoots well in another 59 may not shoot as well in your gun.